Direct polycondensation of N-trimellitylimido-l-leucine with aromatic diamines

N-trimellitylimido-l-leucine (3) was prepared from the reaction of trimellitic anhydride (1) with l-leucine (2) in toluene solution at refluxing temperature in the presence of triethylamine as a catalyst. The direct polycondensation reaction of the monomer imide–diacid (3) with 4,4′-diaminodiphenylsulfone (4a), 4,4′-diaminodiphenylether (4b), 1,4-phenylenediamine (4c), 1,3-phenylenediamine (4d), 4,4′-diaminodiphenylmethane (4e) and benzidine (4,4′-diaminobiphenyl) (4f) was carried out in a medium consisting of triphenyl phosphite, N-methyl-2-pyrolidone, pyridine, and calcium chloride. The resulting poly(amide–imide)s having inherent viscosities 0.24–0.50 dl g−1 were obtained in high yield and are optically active and thermally stable. All of the above compounds were fully characterized by IR spectroscopy, elemental analyses and specific rotation. Some structural characterization and physical properties of this new optically active poly(amide–imide)s are reported.